1. Field of the Invention
The present invention relates to a contents recording apparatus, recording medium, contents reproducing apparatus, contents transmission method, transmission medium, and contents reception method that allow the user to decrypt encrypted recorded contents for a predetermined period of time.
2. Description of the Related Art
On a recording/reproducing apparatus capable of recording and reproducing contents supplied via broadcasting or a package medium, a variety of limitations are imposed on playing back contents in order to protect the copyright of contents. In digital satellite broadcasting, programs are already broadcast in the pay-per-day system. In this system, a general user who is an audience executes a predetermined purchase operation to pay the program provider for what the user will play back. Then, the user may play back the program on that day as many times as the user wants.
For contents recorded on a recording medium, Japanese Patent Laid-Open Publication No. 2000-149417 discloses a method in which, when the user reproduces contents, a flag is set to indicate that the contents are already reproduced to prevent the user from playing them back more than once.
However, when the user uses a contents recording apparatus to record a broadcast program onto a recording medium in the conventional pay-per-day method, the user is able to play back the program as many times as the user wants.
On the other hand, when copy control information is used to prevent a broadcast program from being recorded, the user is not able to watch a desired scene on the recording/reproducing apparatus as may times as the user wants although the user has paid for the program.
In addition, when contents are supplied only as a broadcasting program in real time in the pay-per-day method, the number of times the program may be played back differs between a user who purchases the program in the morning and a user who purchases the program in the night although they pay for the program the same amount of money.